heatshrink_encoder.h File Reference

#include <stddef.h>
#include "heatshrink_common.h"
#include "heatshrink_config.h"

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Data Structures
struct	hs_index
struct	heatshrink_encoder

Macros
#define	HEATSHRINK_ENCODER_WINDOW_BITS(HSE)   ((HSE)->window_sz2)
#define	HEATSHRINK_ENCODER_LOOKAHEAD_BITS(HSE)   ((HSE)->lookahead_sz2)
#define	HEATSHRINK_ENCODER_INDEX(HSE)   ((HSE)->search_index)

Enumerations
enum	HSE_sink_res { HSER_SINK_OK, HSER_SINK_ERROR_NULL =-1, HSER_SINK_ERROR_MISUSE =-2 }
enum	HSE_poll_res { HSER_POLL_EMPTY, HSER_POLL_MORE, HSER_POLL_ERROR_NULL =-1, HSER_POLL_ERROR_MISUSE =-2 }
enum	HSE_finish_res { HSER_FINISH_DONE, HSER_FINISH_MORE, HSER_FINISH_ERROR_NULL =-1 }

Functions
heatshrink_encoder *	heatshrink_encoder_alloc (uint8_t window_sz2, uint8_t lookahead_sz2)
void	heatshrink_encoder_free (heatshrink_encoder *hse)
void	heatshrink_encoder_reset (heatshrink_encoder *hse)
HSE_sink_res	heatshrink_encoder_sink (heatshrink_encoder *hse, uint8_t *in_buf, size_t size, size_t *input_size)
HSE_poll_res	heatshrink_encoder_poll (heatshrink_encoder *hse, uint8_t *out_buf, size_t out_buf_size, size_t *output_size)
HSE_finish_res	heatshrink_encoder_finish (heatshrink_encoder *hse)

Macro Definition Documentation

HEATSHRINK_ENCODER_INDEX

#define HEATSHRINK_ENCODER_INDEX

(

HSE

)

((HSE)->search_index)

Definition at line 32 of file heatshrink_encoder.h.

Referenced by do_indexing(), and find_longest_match().

HEATSHRINK_ENCODER_LOOKAHEAD_BITS

#define HEATSHRINK_ENCODER_LOOKAHEAD_BITS

(

HSE

)

((HSE)->lookahead_sz2)

Definition at line 30 of file heatshrink_encoder.h.

Referenced by get_lookahead_size(), and st_yield_br_index().

HEATSHRINK_ENCODER_WINDOW_BITS

#define HEATSHRINK_ENCODER_WINDOW_BITS

(

HSE

)

((HSE)->window_sz2)

Definition at line 28 of file heatshrink_encoder.h.

Referenced by get_input_buffer_size(), heatshrink_encoder_free(), heatshrink_encoder_reset(), and st_yield_tag_bit().

Enumeration Type Documentation

HSE_finish_res

enum HSE_finish_res

Enumerator
HSER_FINISH_DONE
HSER_FINISH_MORE
HSER_FINISH_ERROR_NULL

Definition at line 21 of file heatshrink_encoder.h.

             {
    HSER_FINISH_DONE,           /* encoding is complete */
    HSER_FINISH_MORE,           /* more output remaining; use poll */
    HSER_FINISH_ERROR_NULL=-1,  /* NULL argument */
} HSE_finish_res;

HSE_poll_res

enum HSE_poll_res

Enumerator
HSER_POLL_EMPTY
HSER_POLL_MORE
HSER_POLL_ERROR_NULL
HSER_POLL_ERROR_MISUSE

Definition at line 14 of file heatshrink_encoder.h.

             {
    HSER_POLL_EMPTY,            /* input exhausted */
    HSER_POLL_MORE,             /* poll again for more output  */
    HSER_POLL_ERROR_NULL=-1,    /* NULL argument */
    HSER_POLL_ERROR_MISUSE=-2,  /* API misuse */
} HSE_poll_res;

HSE_sink_res

enum HSE_sink_res

Enumerator
HSER_SINK_OK
HSER_SINK_ERROR_NULL
HSER_SINK_ERROR_MISUSE

Definition at line 8 of file heatshrink_encoder.h.

             {
    HSER_SINK_OK,               /* data sunk into input buffer */
    HSER_SINK_ERROR_NULL=-1,    /* NULL argument */
    HSER_SINK_ERROR_MISUSE=-2,  /* API misuse */
} HSE_sink_res;

Function Documentation

heatshrink_encoder_alloc()

heatshrink_encoder* heatshrink_encoder_alloc	(	uint8_t	window_sz2,
		uint8_t	lookahead_sz2
	)

Definition at line 78 of file heatshrink_encoder.c.

References get_input_buffer_size(), heatshrink_encoder_reset(), HEATSHRINK_FREE, HEATSHRINK_MALLOC, HEATSHRINK_MAX_WINDOW_BITS, HEATSHRINK_MIN_LOOKAHEAD_BITS, HEATSHRINK_MIN_WINDOW_BITS, hse, LOG, heatshrink_encoder::lookahead_sz2, NULL, heatshrink_encoder::search_index, hs_index::size, and heatshrink_encoder::window_sz2.

Referenced by compress_and_expand_and_check(), data_with_simple_repetition_should_match_with_absurdly_tiny_buffers(), data_without_duplication_should_match_with_absurdly_tiny_buffers(), encode(), encoder_alloc_should_reject_invalid_arguments(), encoder_poll_should_detect_repeated_substring(), encoder_poll_should_detect_repeated_substring_and_preserve_trailing_literal(), encoder_poll_should_indicate_when_no_input_is_provided(), encoder_poll_should_reject_nulls(), encoder_should_emit_data_without_repetitions_as_literal_sequence(), encoder_should_emit_series_of_same_byte_as_literal_then_backref(), encoder_sink_should_accept_input_when_it_will_fit(), encoder_sink_should_accept_partial_input_when_some_will_fit(), encoder_sink_should_reject_nulls(), and gen().

                               {
    if ((window_sz2 < HEATSHRINK_MIN_WINDOW_BITS) ||
        (window_sz2 > HEATSHRINK_MAX_WINDOW_BITS) ||
        (lookahead_sz2 < HEATSHRINK_MIN_LOOKAHEAD_BITS) ||
        (lookahead_sz2 > window_sz2)) {
        return NULL;
    }
    
    /* Note: 2 * the window size is used because the buffer needs to fit
     * (1 << window_sz2) bytes for the current input, and an additional
     * (1 << window_sz2) bytes for the previous buffer of input, which
     * will be scanned for useful backreferences. */
    size_t buf_sz = (2 << window_sz2);

    heatshrink_encoder *hse = HEATSHRINK_MALLOC(sizeof(*hse) + buf_sz);
    if (hse == NULL) { return NULL; }
    hse->window_sz2 = window_sz2;
    hse->lookahead_sz2 = lookahead_sz2;
    heatshrink_encoder_reset(hse);

#if HEATSHRINK_USE_INDEX
    size_t index_sz = buf_sz*sizeof(uint16_t);
    hse->search_index = HEATSHRINK_MALLOC(index_sz + sizeof(struct hs_index));
    if (hse->search_index == NULL) {
        HEATSHRINK_FREE(hse, sizeof(*hse) + buf_sz);
        return NULL;
    }
    hse->search_index->size = index_sz;
#endif

    LOG("-- allocated encoder with buffer size of %zu (%u byte input size)\n",
        buf_sz, get_input_buffer_size(hse));
    return hse;
}

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heatshrink_encoder_finish()

HSE_finish_res heatshrink_encoder_finish

(

heatshrink_encoder *

hse

)

Definition at line 260 of file heatshrink_encoder.c.

References FLAG_IS_FINISHING, heatshrink_encoder::flags, HSER_FINISH_DONE, HSER_FINISH_ERROR_NULL, HSER_FINISH_MORE, HSES_DONE, HSES_FILLED, HSES_NOT_FULL, LOG, NULL, and heatshrink_encoder::state.

Referenced by compress_and_expand_and_check(), data_with_simple_repetition_should_match_with_absurdly_tiny_buffers(), data_without_duplication_should_match_with_absurdly_tiny_buffers(), encoder_finish_should_reject_nulls(), encoder_poll_should_detect_repeated_substring(), encoder_poll_should_detect_repeated_substring_and_preserve_trailing_literal(), encoder_should_emit_data_without_repetitions_as_literal_sequence(), encoder_should_emit_series_of_same_byte_as_literal_then_backref(), encoder_sink_read(), and gen().

                                                                  {
    if (hse == NULL) { return HSER_FINISH_ERROR_NULL; }
    LOG("-- setting is_finishing flag\n");
    hse->flags |= FLAG_IS_FINISHING;
    if (hse->state == HSES_NOT_FULL) { hse->state = HSES_FILLED; }
    return hse->state == HSES_DONE ? HSER_FINISH_DONE : HSER_FINISH_MORE;
}

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heatshrink_encoder_free()

void heatshrink_encoder_free

(

heatshrink_encoder *

hse

)

Definition at line 114 of file heatshrink_encoder.c.

References HEATSHRINK_ENCODER_WINDOW_BITS, and HEATSHRINK_FREE.

Referenced by compress_and_expand_and_check(), data_with_simple_repetition_should_match_with_absurdly_tiny_buffers(), data_without_duplication_should_match_with_absurdly_tiny_buffers(), encode(), encoder_poll_should_detect_repeated_substring(), encoder_poll_should_detect_repeated_substring_and_preserve_trailing_literal(), encoder_poll_should_indicate_when_no_input_is_provided(), encoder_poll_should_reject_nulls(), encoder_should_emit_data_without_repetitions_as_literal_sequence(), encoder_should_emit_series_of_same_byte_as_literal_then_backref(), encoder_sink_should_accept_input_when_it_will_fit(), encoder_sink_should_accept_partial_input_when_some_will_fit(), encoder_sink_should_reject_nulls(), and gen().

                                                      {
    size_t buf_sz = (2 << HEATSHRINK_ENCODER_WINDOW_BITS(hse));
#if HEATSHRINK_USE_INDEX
    size_t index_sz = sizeof(struct hs_index) + hse->search_index->size;
    HEATSHRINK_FREE(hse->search_index, index_sz);
    (void)index_sz;
#endif
    HEATSHRINK_FREE(hse, sizeof(heatshrink_encoder) + buf_sz);
    (void)buf_sz;
}

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heatshrink_encoder_poll()

HSE_poll_res heatshrink_encoder_poll	(	heatshrink_encoder *	hse,
		uint8_t *	out_buf,
		size_t	out_buf_size,
		size_t *	output_size
	)

Definition at line 198 of file heatshrink_encoder.c.

References output_info::buf, output_info::buf_size, do_indexing(), heatshrink_encoder::flags, HSER_POLL_EMPTY, HSER_POLL_ERROR_MISUSE, HSER_POLL_ERROR_NULL, HSER_POLL_MORE, HSES_DONE, HSES_FILLED, HSES_FLUSH_BITS, HSES_NOT_FULL, HSES_SAVE_BACKLOG, HSES_SEARCH, HSES_YIELD_BR_INDEX, HSES_YIELD_BR_LENGTH, HSES_YIELD_LITERAL, HSES_YIELD_TAG_BIT, LOG, NULL, output_info::output_size, st_flush_bit_buffer(), st_save_backlog(), st_step_search(), st_yield_br_index(), st_yield_br_length(), st_yield_literal(), st_yield_tag_bit(), and heatshrink_encoder::state.

Referenced by compress_and_expand_and_check(), data_with_simple_repetition_should_match_with_absurdly_tiny_buffers(), data_without_duplication_should_match_with_absurdly_tiny_buffers(), encoder_poll_should_detect_repeated_substring(), encoder_poll_should_detect_repeated_substring_and_preserve_trailing_literal(), encoder_poll_should_indicate_when_no_input_is_provided(), encoder_poll_should_reject_nulls(), encoder_should_emit_data_without_repetitions_as_literal_sequence(), encoder_should_emit_series_of_same_byte_as_literal_then_backref(), encoder_sink_read(), and gen().

                                                                    {
    if ((hse == NULL) || (out_buf == NULL) || (output_size == NULL)) {
        return HSER_POLL_ERROR_NULL;
    }
    if (out_buf_size == 0) {
        LOG("-- MISUSE: output buffer size is 0\n");
        return HSER_POLL_ERROR_MISUSE;
    }
    *output_size = 0;

    output_info oi;
    oi.buf = out_buf;
    oi.buf_size = out_buf_size;
    oi.output_size = output_size;

    while (1) {
        LOG("-- polling, state %u (%s), flags 0x%02x\n",
            hse->state, state_names[hse->state], hse->flags);

        uint8_t in_state = hse->state;
        switch (in_state) {
        case HSES_NOT_FULL:
            return HSER_POLL_EMPTY;
        case HSES_FILLED:
            do_indexing(hse);
            hse->state = HSES_SEARCH;
            break;
        case HSES_SEARCH:
            hse->state = st_step_search(hse);
            break;
        case HSES_YIELD_TAG_BIT:
            hse->state = st_yield_tag_bit(hse, &oi);
            break;
        case HSES_YIELD_LITERAL:
            hse->state = st_yield_literal(hse, &oi);
            break;
        case HSES_YIELD_BR_INDEX:
            hse->state = st_yield_br_index(hse, &oi);
            break;
        case HSES_YIELD_BR_LENGTH:
            hse->state = st_yield_br_length(hse, &oi);
            break;
        case HSES_SAVE_BACKLOG:
            hse->state = st_save_backlog(hse);
            break;
        case HSES_FLUSH_BITS:
            hse->state = st_flush_bit_buffer(hse, &oi);
        case HSES_DONE:
            return HSER_POLL_EMPTY;
        default:
            LOG("-- bad state %s\n", state_names[hse->state]);
            return HSER_POLL_ERROR_MISUSE;
        }

        if (hse->state == in_state) {
            /* Check if output buffer is exhausted. */
            if (*output_size == out_buf_size) return HSER_POLL_MORE;
        }
    }
}

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heatshrink_encoder_reset()

void heatshrink_encoder_reset

(

heatshrink_encoder *

hse

)

Definition at line 126 of file heatshrink_encoder.c.

References heatshrink_encoder::bit_index, heatshrink_encoder::buffer, heatshrink_encoder::current_byte, heatshrink_encoder::flags, HEATSHRINK_ENCODER_WINDOW_BITS, HSES_NOT_FULL, heatshrink_encoder::input_size, heatshrink_encoder::match_length, heatshrink_encoder::match_scan_index, memset, heatshrink_encoder::outgoing_bits, heatshrink_encoder::outgoing_bits_count, and heatshrink_encoder::state.

Referenced by compress_and_expand_and_check(), and heatshrink_encoder_alloc().

                                                       {
    size_t buf_sz = (2 << HEATSHRINK_ENCODER_WINDOW_BITS(hse));
    memset(hse->buffer, 0, buf_sz);
    hse->input_size = 0;
    hse->state = HSES_NOT_FULL;
    hse->match_scan_index = 0;
    hse->flags = 0;
    hse->bit_index = 0x80;
    hse->current_byte = 0x00;
    hse->match_length = 0;

    hse->outgoing_bits = 0x0000;
    hse->outgoing_bits_count = 0;

    #ifdef LOOP_DETECT
    hse->loop_detect = (uint32_t)-1;
    #endif
}

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heatshrink_encoder_sink()

HSE_sink_res heatshrink_encoder_sink	(	heatshrink_encoder *	hse,
		uint8_t *	in_buf,
		size_t	size,
		size_t *	input_size
	)

Definition at line 145 of file heatshrink_encoder.c.

References heatshrink_encoder::buffer, do_indexing(), find_longest_match(), get_input_buffer_size(), get_input_offset(), hse, HSER_SINK_ERROR_MISUSE, HSER_SINK_ERROR_NULL, HSER_SINK_OK, HSES_FILLED, HSES_NOT_FULL, heatshrink_encoder::input_size, is_finishing(), LOG, memcpy, NULL, hs_index::size, st_flush_bit_buffer(), st_save_backlog(), st_step_search(), st_yield_br_index(), st_yield_br_length(), st_yield_literal(), st_yield_tag_bit(), and heatshrink_encoder::state.

Referenced by compress_and_expand_and_check(), data_with_simple_repetition_should_match_with_absurdly_tiny_buffers(), data_without_duplication_should_match_with_absurdly_tiny_buffers(), encoder_poll_should_detect_repeated_substring(), encoder_poll_should_detect_repeated_substring_and_preserve_trailing_literal(), encoder_should_emit_data_without_repetitions_as_literal_sequence(), encoder_should_emit_series_of_same_byte_as_literal_then_backref(), encoder_sink_read(), encoder_sink_should_accept_input_when_it_will_fit(), encoder_sink_should_accept_partial_input_when_some_will_fit(), encoder_sink_should_reject_nulls(), and gen().

                                                          {
    if ((hse == NULL) || (in_buf == NULL) || (input_size == NULL)) {
        return HSER_SINK_ERROR_NULL;
    }

    /* Sinking more content after saying the content is done, tsk tsk */
    if (is_finishing(hse)) { return HSER_SINK_ERROR_MISUSE; }

    /* Sinking more content before processing is done */
    if (hse->state != HSES_NOT_FULL) { return HSER_SINK_ERROR_MISUSE; }

    uint16_t write_offset = get_input_offset(hse) + hse->input_size;
    uint16_t ibs = get_input_buffer_size(hse);
    uint16_t rem = ibs - hse->input_size;
    uint16_t cp_sz = rem < size ? rem : size;

    memcpy(&hse->buffer[write_offset], in_buf, cp_sz);
    *input_size = cp_sz;
    hse->input_size += cp_sz;

    LOG("-- sunk %u bytes (of %zu) into encoder at %d, input buffer now has %u\n",
        cp_sz, size, write_offset, hse->input_size);
    if (cp_sz == rem) {
        LOG("-- internal buffer is now full\n");
        hse->state = HSES_FILLED;
    }

    return HSER_SINK_OK;
}

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